I bought my first iPhone last week and within days used it to make my inaugural foray into mobile commerce -- purchasing a pair of shoes from Urban Outfitters. I logged onto the retail site at home after dinner and, with the shoes in my shopping cart, all I had to do was enter a credit-card number. Consumers can skip that step, too, if they want the site to store the number. The shoes arrived within days. I bought the iPhone because I couldn't stand to be away from my favorite online sites when I wasn't at my desk at home or at work. Now I have access whether I'm having breakfast, in a taxicab, on a trip or simply waiting for a friend at a restaurant.

People with Web-enabled phones make up about 10 percent of U.S. cell phone owners, and that number is only going to grow. Sears mobile innovations team leader Thomas Emmons put it well when the retailer launched its mobile Web site, Sears2go, in November: "If you're marketing to people who read 85 percent of their e-mails on a BlackBerry, and you don't have a good mobile site, you're losing that customer," he said.

Shopping by mobile phone won't replace online stores any more than ecommerce has replaced brick-and-mortar stores. It is an extension of electronic shopping that is a potential win-win for both consumers and retailers.